I work on a variety of problems in gravitational physics, plasma physics and astrophysics, with an emphasis on the regime where gravity and electromagnetism are strong. A unifying theme is that strong fields make for interesting physics and theoretical simplification that enables clean study of important processes. I like to work on problems that have both intrinsic interest and astrophysical application. Recent interests have included the two-body problem in general relativity, electromagnetic and gravitational self-force effects on the motion of bodies, strong-field (force-free) plasmas and quantum-electrodynamical corrections, and physics near rapidly rotating black holes.